Abstract

Afforestation and ecological restoration have often been carried out with fast-growing exotic tree species because of their high apparent growth and yield. Moreover, fast-growing forest plantations have become an important component of mitigation measures to offset greenhouse gas emissions. However, information on the long-term performance of exotic and fast-growing species is often lacking especially with respect to their vulnerability to disturbance compared to native species. We compared carbon (C) storage and C accumulation rates in vegetation (above- and belowground) and soil in 21-year-old exotic slash pine (Pinus elliottii Engelm.) and native Masson pine (Pinus massoniana Lamb.) plantations, as well as their responses to a severe ice storm in 2008. Our results showed that mean C storage was 116.77 ± 7.49 t C ha−1 in slash pine plantation and 117.89 ± 8.27 t C ha−1 in Masson pine plantation. The aboveground C increased at a rate of 2.18 t C ha−1 year−1 in Masson pine and 2.23 t C ha−1 year−1 in slash pine plantation, and there was no significant difference in C storage accumulation between the two plantation types. However, we observed significant differences in ice storm damage with nearly 7.5 % of aboveground biomass loss in slash pine plantation compared with only 0.3 % loss in Masson pine plantation. Our findings indicated that the native pine species was more resistant to ice storm because of their adaptive biological traits (tree shape, crown structure, and leaf surface area). Overall, the native pine species might be a safer choice for both afforestation and ecological restoration in our study region.

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Acknowledgments

We would like to express our deepest thanks to Prof. Susan Trumbore for her helpful suggestions in composing this paper. We greatly appreciate Dali Guo and Luke McCormack, for their advice in this study. The authors would like to thank the anonymous reviewers for their comments that helped improve the manuscript. This work is financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences and Climate Change: Carbon Budget and Relevant Issues (XDA05070302), National Natural Science Foundation of China (31100324, 31070559), as well as the MPG-CAS doctoral training program.

Appendix

Land-use history and ecosystem characteristics in research site

Natural vegetation in the study area is broadleaf forest. However, deforestation and other human disturbances caused massive soil erosion in the past and prevented successful natural regeneration. In the 1970s, residual Masson pine forests were cut and replaced with sugar cane (Saccharum sinense Roxb.) cultures, but this kind of vegetation was not well suited for the site conditions and the cultures failed completely and were abandoned (SITCAS 1989).

Carbon content of branch (left panel) and foliage (right panel) biomass in different crown sections of the two plantation types (MP Masson pine; SP slash pine). There was no consistent trend in carbon content in relation to crown position (t test, P > 0.05) or between branches and foliage of the two species (t tests, branch: P = 0.288; foliage: P = 0.929)

Table 4

Chemical and physical characteristics of upper 40-cm soil in pine plantation as measured in Qianyanzhou in 2006

Depth (cm)

Masson pine

Slash pine

Bulk density (g m−3)

0–10

1.36 ± 0.10

1.42 ± 0.08

10–20*

1.50 ± 0.16

1.49 ± 0.09

20–30

1.48 ± 0.11

1.57 ± 0.10

30–40

1.52 ± 0.12

1.64 ± 0.24

Soil organic C (mg g−1)

0–10

12.6 ± 2.4

12.2 ± 3.8

0–20

7.4 ± 1.4

6.3 ± 1.6

20–30

5.5 ± 1.4

4.3 ± 1.2

30–40

3.9 ± 0.6

3.0 ± 1.1

Total nitrogen (mg g−1)

0–10

0.80 ± 0.18

0.91 ± 0.25

0–20

0.59 ± 0.09

0.57 ± 0.11

20–30

0.52 ± 0.14

0.46 ± 0.09

30–40

0.43 ± 0.06

0.39 ± 0.13

* Indicated a significant difference between two plantations at P < 0.05

Table 5

The simulation of Masson pine (MP) and slash pine (SP) when ice weight loaded on crown